The RAS2020 production concept is for real challenging the traditional cage farming. Not just due to the sustainability element, but with this technology, it will be possible to produce fish like trout and Salmon at a comparable cost, but first at all, compared to previous technologies for landbased farming, the fish can be produced to a more uniform size, and it will from even a modest anual production volume be possible to produce a predictable even daily harvest from the facility.
Daily predictable supplies, and a uniform size of fish are two key factors for achiving a high price for the products in the market.
Some of the key commercial advantages with the RAS2020 technology are listed below:
a) All essential critical piping has been eliminated in construction.
A major risk in building RAS facility has always been the piping work. Once the piping is well below the ground underneath concrete structures and tanks, there is little to do about it. But in the case a welder has forgotten to remove a single rib after welding a joint, then it may have catastrophically impact on flow capacities within the system. In the RAS2020 all essential piping has been eliminated. This is a safety factor, but it is also reccing the construction costs, and the time to build the facility.
b) Reduced production volume compared to feeding/production capacity.
The total production volume compared to production capacity is much smaller than seen in any previous systems, and that without compromising fish density. This is an important feature when farming fish in Seawater due to the CO2-Bicarbonate equilibrium, where a high treatment frequency is desired. The RAS 20020 system, has a production volume of only 1,25 m3 per kilo of feeding, still with an internal exchange rate per kilo of feed of approx. 60 m3 per kilo of feed. A combination hardly seen before when dealing with production of fish up to 3-4 kilos, but essential for securing both economy in production and a steady low CO2/bicarbonate level, as required for optimal growth performance.
c) A laminar horizontal flow, of a speed, which is optimal for fish performance.
The horizontal laminar flow speed of 0,5-0,8 meter per second is not only essential for stable water quality, avoiding the sedimentation but what is required for several fish species, especially the salmonids, for obtaining optimal growth and a high protein level in the fish fillet.
Systems with vertical turbulent flow structures are not suitable for these fish, which are means which some inventions have applied to establish a uniform water quality in a fish tank, but without much success in practice as this is not in line with the requirements of the fish, which will only perform well with a horizontal flow pattern.
d) Uniform flow pattern for all fish within the same group/grade of fish,
The laminar uniform horizontal flow generated by the installed flow setters, generates an almost even water velocity within each of the tank sections, at a speed which is optimal to the fish, which can be obtained even with the grids in place. A flow speed which cannot be obtained by injection water only. Even with a tank exchange of 1,5 exchanges per hour, the injection of new water in the tank only counts for less than 7 % of the tank flow.
In a single section the retention time of water will be as low as 30 seconds, basically meaning the water quality will be the same to all the fish within the tank section- essential to secure even growth among the fish, as dominating fish cannot take advantage of taking a better position within the tank, furthermore with sequence feeding between the tanks, fluctuations in general within the entire tank can be evened out, meaning the water quality throughout a 24 hour period, will be much more stable than in a single tank concept, where high fluctuations will be at seen. Steady and uniform water quality is essential for optimal and uniform growth performance among the fish in the batch/group.
e) Fluctuations in water chemistry within tank sections as well as over time very minimised
compared to other systems.
Fish are much more sensitive to fluctuations in water quality parameters, than to the absolute values themselves. This especially regarding pH, CO2 and Oxygen. By having 8-10 separated groups of fish within the same tank as the RAS2020 technology has been planned for, and on the same water flow, and with a frequenced feeding over a 24 hours period, the fluctuations will be balanced out. In case of 5 feedings per section per day, in 8 sections, that makes it a feeding roughly twice per hour on average, with the consequence of an even load within the system, and still with all the fish within a tank section exposed to the same water quality, due to an 100% average exchange rate of the section of less than 30 seconds.
In both circular tanks and D-ended raceways there is a step gradient especially on pH and potentially on oxygen from the periphery of the tank towards the centre part, as from top to bottom, as the current pattern also will be different across the tank. This will make the stronger fish take the best positions, while the weaker fish are left with the less favourable spots, and depressed more on growth, increasing the requirements for grading, or alternatively when producing a bigger grade of fish, where grading is not an option, with the consequence of a bigger size variation at harvest, reducing the average selling price.
The pH gradient is critical to the fish – growth and feed conversion, as it indicates the difference on CO2/bicarbonate level which the fish will be exposed to.
f) Option for efficient daily harvest of fish, from a single production unit, without disturbance of
remaining fish in system, and without stress impact on fish due to pumping of the fish
/elevating the fish above tank edge.
A problem which most land based farmers have faced, has been the limitation to harvest fish on a daily basis, throughout the year, which on the other hand is essential, for obtaining a high price for the products.
The salmon industry is dominated by companies, who produce + 80.000 tons of fish per year, so for them it is not a problem just to empty a cage of two for harvest.
But with a limited production and a limited number of fish tanks, it is not a good option to stop feeding a tank of fish for a week or more, just to take out a portion of the fish.
Even from a single RAS2020 production unit, it will be possible to take out fish every day without disturbing the fish not to be harvested, and to take the fish out without stressing them by having to pump them out of the production tank.
This is not new, but in the RAS2020 the feature has been integrated into the system design, to be managed in a simple and efficient way.
g) Reduced blueprint, reduced cost for land and construction.
The RAS2020 operates with a blueprint much smaller than any previous design for fish to be produced to a size of plus 3 kilos.
This jointly with the elimination of essential underground piping, makes the investment per ton of production, considerable less compared to the investments in a conventional farm. The space required for a 1200 tom module of 3-4 kilo of Steelhead salmon (1800 ton trout of 400 gram) is less than 3000 m2.